Alpha particles. Alpha particles are made of 2 protons and 2 neutrons. This means that they have a charge of +2, and a mass of 4. (the mass is measured in atomic mass units, where each proton & neutron=1) We can write them as , or, because they're the same as a helium nucleus, . Alpha particles are relatively slow and heavy.
For more, visit TIME Health. 1  The average attention span for the notoriously ill-focused goldfish is nine seconds, but according to a new study from Microsoft Corp., people now generally lose concentration after eight seconds, highlighting the affects of an increasingly digitalized lifestyle on the brain.
Length of Presentation. 1  The average attention span of an adult is 20 minutes. 2  Implication: you should ensure that the first 20 minutes of your talk include any material that you want your audience to remember. The same is true of your talk. 2  Do not bury the main results in the middle of the talk. 3  Not only might the audience miss them but you might be past your audience's 20 minute attention span and they'll have already tuned you out.