From Bulbapedia, the community-driven Pokémon encyclopedia.
The Pewter Museum of Science (Japanese: ニビかがくはくぶつかん Nibi Museum of Science) is located in the north side of Pewter City, Kanto, and is one of the city's main attractions. The Pewter Museum of Science hosts a wide range of attractions and exhibits, largely based around space and fossil exploration. The museum holds a huge collection of artifacts, including rocks from the moon, space shuttles, and fossils of ancient Pokémon. The admission is 50 for a child's ticket.
In the games
There are two floors to explore in the Pewter Museum of Science. The first floor holds the front desk, and a fossil exhibit containing the fossils of Aerodactyl and Kabutops. Missingno. may use these sprites depending on its index number. The second floor hosts a space exhibit, featuring a Space Shuttle and Moon Stone that fell onto Mt. Moon. The player is able to explore the museum at any time, after paying the 50 admission fee.
Once the ability to use Cut out of battle is gained, the player can sneak into the back of the museum and acquire the Old Amber from a scientist there, allowing the player to revive an Aerodactyl later in the game. In FireRed and LeafGreen, there is also a move tutor who will teach Seismic Toss.
In Generation II, the museum is closed due to renovations.
In Generation IV the museum is open for business, but the major exhibitions are elsewhere so entry is free. There is only one floor in this generation. There is a scientist in the museum who will revive a player's fossils, much like the scientist at Cinnabar Island's Pokémon Lab in Generation I and FireRed and LeafGreen. This is due to the fact that fossils can be found under rocks using Rock Smash, unlike in Generation II where players were required to transfer Fossil Pokémon from the Generation I games using the Time Capsule. Steven Stone, former Champion of the Hoenn region, will also appear here, offering his Beldum in exchange for a Forretress.
The Pewter Museum of Science hosts a wide array of different exhibits and attractions. The first floor contains fossil exhibits, including fossils of Aerodactyl and Kabutops, the rare, prehistoric Pokémon. The second floor has a space exhibit featuring a model of a Space Shuttle, and a rock, most likely a Moon Stone, that fell onto Mt. Moon in the form of a meteorite.
In the Generation I games and their Generation III remakes, an old man on the second floor of the museum states, "July 20, 1969! Humankind first set foot on the moon that day. I bought a color TV just so I could watch that news." July 20, 1969 was indeed the date that humans first landed on Earth's Moon in the real world.
Enigma Stone Event
In HeartGold and SoulSilver, if the event item, Enigma Stone, is taken to the Pewter Museum of Science, traveling Pokémon Champion Steven Stone will have a researcher from the museum examine the stone. The researcher then discovers that it is really the Soul Dew, an item said to be the crystallized souls of Latias and Latios. After this brief encounter, depending on the game version, one of the twin dragons will appear outside of the Museum, giving the player an opportunity to capture it. If the player does not engage in a battle with the Latios or Latias, it will remain there until the player has done so.
In other media
In the manga
In the Pokémon Adventures manga, Brock works as a security guard at the museum. It was there that he somehow managed to revive and acquire a Kabuto that later evolved into Kabutops. Later, however, the museum is burned down by two Magmar. Red used Sand, a Sandshrew he caught throughout his voyages with Giovanni, to annoy the Magmar in Make Way For Magmar! in the Red, Green & Blue Chapter. Red used his Sandshrew to use Sand-Attack to freeze them in sand. But Giovanni later finished them off with his Cloyster when the Magmar regained consciousness.
In the anime
In the anime, Seymour is a researcher from the museum, but this isn't mentioned in the dub.