This video can not be played Former England goalkeeper Joe Hart answers your questions about the Trionda World Cup ball and and explains how it might be affecting goalkeepers at the tournament. READ MORE: Is the World Cup ball making it hard for goalkeepers? Available to UK users only.

Geysers show us there's plenty of heat in the earth's crust It's hard to get Democrat and Republican politicians to agree on much at the moment, but the benefits of geothermal energy is one rare area of consensus. Geothermal energy makes use of natural heat below the Earth's surface and the next generation of technology can access hotter, deeper and more varied locations than ever before. Broadly, the low greenhouse gas emissions of geothermal plants appeals to liberals, while conservatives like the additional energy independence of geothermal, plus the use of drilling technology familiar in the oil and gas industry. Some US states are trying to accelerate permits for geothermal plants and in April senators from both parties introduced the Next-Generation Geothermal , external Research and Development Act. The legislation would direct the Department of Energy to support the development and commercialisation of the next generation of geothermal energy systems. One emerging type is known as enhanced geothermal systems (EGS). In EGS, underground rock is fractured hydraulically. That's done by pumping pressurised fluid into one well, and then collecting steam or hot water from another well. Better known as fracking, this technique has become well known and controversial ( particularly in the UK ) in the oil and gas industry. "It's the same techniques and up to a point it's the same industry as well," sums up Gernot Wagner, a climate economist at Columbia Business School in New York. But "from a climate perspective, there's a huge difference," he adds. For him, the risk of seismic activity, by creating cracks underground, is outweighed by the benefits of an energy source that is renewable, always-on and large-capacity. "Based on where we are, moving much faster, much bigger in the direction of using much more geothermal, frankly, is all good news," Wagner says. Quaise uses concentrated millimetre-waves to vaporise rock To go faster and deeper will require advances in drilling technologies. Companies are developing drilling equipment that is more stable when breaking through hard rock at high temperatures. Some firms are even aiming to penetrate rock without using standard drills. Quaise, a company with roots at the Massachusetts Institute of Technology (MIT), is using a technology called millimetre wave drilling. The frequency is similar to that of microwaves. Quaise's application involves "sending electromagnetic waves in the microwave millimetre wave spectrum to essentially melt and vaporise through the rock," explains Harry Kelso, Quaise's communications manager. Traditional geothermal energy clusters around hotspots on the earth's surface where very hot rocks can be easily accessed. "Millimetre wave drilling really enables you to access super-hot geothermal just about anywhere in the world," says Kelso. While Quaise is planning to use some conventional drilling at the project site it's developing in Oregon, Kelso says that conventional drills start to break down more quickly when it reaches very hard rock. Replacing drill bits increases the cost and time of drilling. In Quaise's case, Kelso says, "millimetre wave drilling is really what changes that because we're not using a physical drill bit." Other companies are also working on advanced drilling technology, such as projectiles that move several times faster than the speed of sound. Another crucial resource in the process is water. While some types of next-generation geothermal could create risks of water contamination or overconsumption, careful design can avoid this problem. Initially Quaise's system requires a lot of water, but according to Kelso, once the water is in the system it is continually circulated over the super-hot rocks. "We're essentially just recycling the water over and over," he says. Quaise is continuing to raise funds, with the aim of its Oregon project being up and running by 2030. Like other early versions of geothermal systems, it's an expensive project to get up and running. "The economics are somewhat challenging," Kelso admits. "Geothermal today is still more expensive because you are not getting as much power out of the well as you would if you were using that well for fossil fuel." But Quaise hopes that by targeting very high temperatures, of between 300C and 500C, the economics will improve. While the higher end of that temperature range is ambitious, it's a case of the-hotter-the-better. "It allows you to get 10 times more energy per well from geothermal, which changes the economics and the power potential of geothermal," according to Kelso. Quaise says its tech will bring geothermal energy to more regions In May, the Texas company Fervo Energy generated huge interest by becoming the first next-generation geothermal company to become publicly traded. It was initially valued at around $7.7bn. At the time of writing, shares are up around 18% from their IPO price. Fervo quotes a construction cost for its Utah plant of $7,000 per kilowatt of electricity, which it says is comparable to traditional nuclear power , external . And while that's expensive, Fervo points out that, like other renewable energy sources, it does not have any ongoing costs for fuel. "Over time, our goal is to achieve scale and drive down prices such that we're able to outcompete gas," the company said in its IPO filing. Fervo has one high-profile customer - in 2021 it signed a deal , external sell its energy to Google, which needs vast amounts of electricity of its new datacentres. It also has backing from Breakthrough Energy, a venture by Microsoft founder Bill Gates , external to accelerate innovative electricity production. Geothermal firm Fevro listed on the Nasdaq in May Such investment is badly needed for next-gen geothermal firms, which have enormous capital costs. Datacentre projects alone won't be enough to move the needle, according to the International Energy Agency. Both customer demand and costs remain uncertain. The climate solutions organisation Project Drawdown , external notes that "early projects carry a significant risk of cost overruns". Nevertheless Columbia researcher Wagner believes geothermal has tremendous potential and is not just hype. He emphasises that commodities like oil, gas and coal are vulnerable to political disruption, but "geothermal is a technology" and more secure. Wagner is confident that geothermal energy has now achieved liftoff, and will only get better and cheaper over time. Correction 26 June: This article was updated to clarify that the $7,000 per kilowatt of electricity figure was related to construction costs and not energy production. 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How to be a good tennis parent By the time Ellie-Rose Griffiths was nine, she had left school to train full-time. That was when tennis stopped being just a game and became her life. The former top-ranked junior player would go on to compete alongside some of the top names in British tennis including Katie Boulter, Emma Raducanu and Harriet Dart before stopping playing at 19 because she was burned out and not enjoying it any more. When the 27-year-old looks back now, it is not just the tennis she remembers. It is the pressure around it, and in particular one group of people she believes could deal with it better. Parents. Pushy parents are nothing new in a sport offering the potential of millions of pounds in prize money at the very top - at elite level there are well-documented incidents involving the dads of Jelena Dokic, Mary Pierce and Bernard Tomic to name a few. It all starts at junior level. "You see parents shouting at children all the time in tennis," says Griffiths, whose criticism is not for her own supportive parents but for what she has seen in the game. "There's a lack of understanding on how they should behave... on how they could help their child to blossom into the athlete that they should become." And it can get out of hand. "We've had situations here before where unfortunately we've had to call the police because the parents' behaviour is getting that far out of control," says Chris Johnson, head coach at Sutton Coldfield Tennis Club, where he has worked for 36 years. "They won't listen, they think they can get away with anything, they don't respect the referees, it can get a bit ugly." Both are clear that behaviour like that does not happen in isolation and that it is the environment tennis creates that makes parents behave this way. So, why is that and what needs to change? Tennis can be intense for parents. There is transport to arrange, coaching to fund, and a complicated player pathway to navigate. In some cases there's even private tutoring to arrange if their child has left mainstream school to focus on the sport. "You do get on a bit of a hamster wheel", says John from Derbyshire, whose 11-year-old son Harrison is a promising player. "It's 12 months of the year, indoor courts and outdoor courts." Children can start a form of tennis from the age of four on a modified court. The Lawn Tennis Association's (LTA) performance pathway for the most promising juniors supports players from the age of seven on their journey to potentially becoming a Grand Slam champion. Competitions are grouped according to age and start aged eight and under. And the ratings and rankings you get from doing them are one way to get noticed. So when does it start to get serious? "The minute they start playing their first competition," according to Johnson. Does he think that is right? "Absolutely not. "A lot of adults can't cope with the pressures of playing an individual sport and then they're expecting young children to be able to do so." Steve Whelan, a coach working in St Albans with nearly three decades of experience, agrees that the system places too much emphasis on winning at a young age. "It just creates this race to the bottom because parents are chasing ratings and rankings," he says. He tells parents: "These are not tennis players. They are kids who play tennis and there's a big difference." The LTA says it undertook a "comprehensive review" of its rating and ranking system in 2018 "specifically to address the issue of putting too much pressure on children at too young an age." Now players can't be ranked nationally against their peers until they reach the under-11 age group, with younger children from eight and up organised into competition based on recent form - a rating. When it comes to parental behaviour the LTA says like any sport "there are occasions when a small minority of parents do not uphold the standards of behaviour expected". The governing body will soon be launching a new initiative called Fair Play, to promote positive parent behaviour and support coaches. Ellie-Rose Griffiths is a former British junior number one For parents, the pressure is not only emotional. It can also be financial. "It just gets more and more: lessons, travel, flights, tournament fees..." one parent explains. Griffiths puts numbers on it. "If you want to play four hours a day with a coach... that's £1,000 a week... £4,000 a month... that's more than people's salaries," she says. The LTA says it "supports talented junior players through access to world-class coaching and facilities across our network of Regional Performance Development Centres". The governing body also offers grants to young players on its performance pathway who are facing financial barriers to training, travel or competition, through its foundation. But Griffiths says parents investing to bring their children to the next level can alter behaviour. "The financial support comes from the winning and the losing," she says. "If my child wins, I might get some more funding; if my child loses, we might not - so we don't want them to lose." Johnson recognises the shift. "They are almost expecting a return on their investment, and it shouldn't be like that." This video can not be played Being a tennis parent "A 10-year-old isn't expected to do a job, but it does become that," Griffiths says. It is a view echoed by Australian Todd Ley, who was once touted as the best junior player in the world and at 12 became the youngest athlete ever signed by global sports agency IMG before quitting the sport at 17. He trained at the Nick Bollettieri academy in Florida, where the Williams sisters, Andre Agassi and Maria Sharapova were among the famous names associated with the programme. Andy Murray and Juan Martin Del Potro were some of the junior players he measured himself against. Tennis quickly became all-consuming, says Ley, and "tennis went from enjoyment to employment". He ended up "hating" tennis and still does. His dad Max was his coach and manager. From Ley's perspective, tennis came first for his dad, and his son came second. "Realistically, it was tennis from, you know, breakfast to bedtime," says Ley, who has written about his experiences in Smashed: Tennis Prodigies, Parents and Parasites. "Very quickly, the child isn't looked at as a person. They are a commodity and a stock." Ley believes early success in tennis can create incentives that push families, coaches and systems towards doing more, earlier. "If you have very good results early then you're going to get a better ride and you're going to get better management companies, sponsors," he says. "Very early it becomes a contest about who can do more. "People forget completely that they're dealing with children." Todd Ley was the top 12-year-old tennis player in the world but quit at 17 Not everyone minds having pushy parents - or at least not in hindsight. Emma Raducanu has previously described hers as "so pushy" when she was younger. In an interview with the Times in 2024 she said: "I've seen some great people who I was playing with in the juniors who had way more lenient parents, who were like, 'It's OK if you lost', and those players don't play tennis any more, so I don't blame my parents for it." And former British number one Kyle Edmund says that while his parents were not pushy, they did push him to improve things like attitude and work ethic. He said he once told his dad he wanted to quit and his dad just said, "OK, let's just stop then". At that point Edmund realised he actually loved the game and wanted to work hard to succeed. "There's definitely times where you see almost like the parent wants it more, and that's when I think it becomes toxic," he told BBC Sport. "It's got to come from the son or daughter to really want to do it. "And I think the best way is when the parents provide an amazing support system to be there for them and encourage them to do better and want to have ambition." Britain's 2021 US Open champion Emma Raducanu has described her parents as 'pushy' For many parents, the shift happens gradually. Rob is watching his son in a group training session, quietly, from a distance. "Your child goes from going along on a Saturday morning to a fun session and before you know it everything's got very serious at a very young age," he says. "You started playing something because of the joy of playing it and that should be what it's all about. But within the system it can be easy to forget that." Ramesh, another parent, says he looks back on his older children's tennis journeys with regret and that he put too much emphasis on results. Now he tells his youngest son to "forget about the winning or losing". Griffiths doesn't criticise her own parents. She is clear her mother, a single parent bringing up three children, was central to everything she achieved. "My mum would admit she wasn't perfect," Griffiths says. "But there was no support there in place for her to know how to be the best tennis parent. "They're ultimately the second most important person in this journey." Liya Jacob has two sons who play tennis and says most parents are trying to do the right thing: "I'm a doctor, I'm a life coach, and I think I'm quite emotionally intelligent, but even I was finding myself, on occasion, slipping into unhelpful behaviours. "It's not that we've got bad parents out there. Parents don't have a framework to help them deal with the challenges of sports." Together with Griffiths and Johnson she set up an online course called Winning Parents, aimed at helping parents understand how they can support their children before, during and after matches. Dr Jacob says parents often fall into two patterns. "One is over-helping," she says. "So what I see a lot of parents do is over-coaching from the sidelines or interfering during matches. Another pattern is that people can get overly critical of their child. "Kids often describe dreading the car ride home after a poor performance, after poor results. Parents don't mean to create these environments but it can easily happen under pressure." The LTA says it offers "a range of resources to parents to educate and inform them about each stage of the pathway". Online they run the Parent Support Programme, developed by leading academic experts. It covers parents' roles at competitions, communication before, during and after matches, and managing the emotional demands of competition. Despite the challenges, Griffiths still has a love for the game. She says tennis gave her skills that have shaped her life beyond the sport, but believes parents need help to understand the power they hold. "I want parents to see that tennis is such an incredible avenue to develop your child's character if you do it in a supportive way," she says. "It can damage your child's character if you do it in the wrong way." Do you have a story to share?

It takes 72 games to reduce the number of teams at the World Cup from 48 to 32 The World Cup has, so far, lacked an element of real jeopardy in the group stage. Granted, South Korea may disagree after a shock 1-0 defeat by South Africa on Wednesday sent Bafana Bafana into the knockout stage for the first time. But it is limited peril, because South Korea are still very likely to reach the last 32 as one of the eight best third-placed teams. A record of three points and goal difference of -1 is probably going to be enough. But had the defeat by South Africa happened at the 2022 World Cup, when only the top two teams in each group qualified, South Korea would already be on the plane home. The addition of third-placed qualifiers is a necessary feature of this new format - to ensure we get 32 teams in the knockout rounds. But it has created additional scenarios in which teams can play for specific results to either qualify or, in effect, pick opponents. Two matches in particular this week are a real test of the format. The first of those games has already produced the convenient draw that should send both teams through. Expanding the World Cup to 48 teams always presented one obvious problem - it was an imperfect number for a tournament. With 32 teams, the maths was simple - eight groups of four teams, with the top two going through to a last 16, then quarter-finals, semi-finals and a final. By adding another 16 nations, Fifa had to find a way to get to a symmetrical knockout stage. There was no ideal solution - one which preserved the intensity of the previous format. The original plan was to create 16 groups of three teams. The two top in each would go through to the last 16. But there was an issue. Three-team groups meant individual fixtures - and those in the final match would know exactly what they needed to do to qualify. Nations could play for specific results to secure their passage to the knockout rounds. Fifa, after all, knew all about alleged collusion from the scandal at the 1982 World Cup . Back then, with groups of four, teams did not play their final group matches at the same time. West Germany faced Austria in the standalone last game. A slender win for the Germans would send both teams through at the expense of Algeria. The match finished 1-0 to West Germany. Algeria went out. Fifa changed the format so all final fixtures would be played simultaneously, but that would not have been possible with three-team groups. The climax to the group stage in Qatar was so exciting that Fifa had a rethink. It accepted there must be 12 four-team groups and two matches would be played at the same time to determine who would qualify. Except for one crucial difference - something that removed much of the jeopardy that made the last World Cup so gripping. Eight of the third-placed teams must go through for there to be 32 teams in the knockout rounds. It became harder to be knocked out than to progress. And one issue becomes clear with two matches this week. First up, Australia played Paraguay on Thursday. The teams were second and third in Group D and both on three points. Four points is almost certain to be enough to take one of the eight third-placed qualifying slots, so it created a situation in which the teams knew that a draw was helpful to both. The match finished 0-0. Australia are definitely through in second place and celebrated with their supporters at the final whistle. Paraguay played it low key but, barring a very unlikely set of results in the remaining groups, they will go through too. The next game of interest in this respect is Austria v Algeria in Group J (03:00 BST Sunday). Again, the two teams are second and third on three points. A point is very likely to send both teams through, while defeat is much more likely to send one home. Will we see another draw? After being impacted negatively in 1982, Algeria could be the beneficiaries in 2026. You could argue a game in Group F on Thursday fell into the same category, with Japan starting the match on four points and Sweden on three. That match also finished 1-1 to guarantee the Scandinavians would progress, but there was no real risk involved for Japan if they have lost. It is the same in Group L, too, with Ghana on four points and Croatia on three. There are many examples of teams playing out the final 10 minutes of a group game with no interest in attacking because they both know they are going through. It does not mean the two teams will just play for a point this week, of course, but it presents the opportunity. At Euro 2020 we had the same circumstances. Ukraine and Austria went into their last match in second and third respectively on three points, aware that four points would probably be enough to go through in third. But the teams did not play out a draw. Austria won 1-0 to move up to second, with Ukraine eventually squeezing through to the last 16. Ukraine were one goal better off than Finland, who lost their last fixture later the same day. The bookmakers are certainly taking no chances. For Australia-Paraguay and Austria-Algeria, the odds offered for a draw have been close to even money. Selling cars & air miles conundrum - what now for Tartan Army? What each team need to reach World Cup knockouts Have World Cup changes made final group stage games unfair? Teams could, of course, play for specific results before third-placed teams qualified. Take one incident at Euro 2004, which led to Italy goalkeeper Gianluigi Buffon and Italian federation president Franco Carraro making accusations of match-fixing . If Sweden-Denmark was a draw and the teams scored at least twice, Italy would finish third because they scored fewer goals in matches between the three sides. Sweden equalised in the 89th minute. The final score? Sweden 2-2 Denmark . Uefa insisted there was nothing suspicious about the result. There is a further twist at this World Cup. The fixtures for the third-placed teams are determined by which groups provide the qualifiers. Play early, and you don't have an idea where you will go if you finish third. Play later, and you know what the path looks like. What does that mean in reality? The runners-up in Group J will play the winners of Group H - Spain are top of the table right now. But where will the third-placed team in Group J go? They could play the Group L winners, perhaps England, or Switzerland who finished top of Group B. Austria and Algeria will know what the last 32 looks like. They could be in a position where finishing third is more favourable than second. Rather than playing for a draw, Austria might feel they are better off losing and taking up that match. The weather may yet play a part too. If there are storms which cause a match to be paused , Fifa says the other game in the group will not be halted. So, one fixture might be suspended for a couple of hours due to lightning, and when the teams comes back out they know what they need to do to qualify. After Australia-Paraguay finished a draw, and with Austria-Algeria to come, there will probably be further questions about the wisdom of the format. This has been Fifa's choice. The expansion of the World Cup was part of the manifesto on which president Gianni Infantino was elected in 2016. Perhaps it will give Infantino a reason to restore the tournament to a perfect number. Not reducing to 32, but increasing to 64. Play BBC Sport's new World Cup predictor game World Cup fixtures and group standings How to watch the World Cup on the BBC Everything you need to know about the World Cup